Benthic nutrient fluxes in the intertidal flat within the Changjiang （Yangtze River） Estuary

In an annual cycle from March 2005 to February 2006, benthic nutrient fluxes were measured monthly in the Dongtan intertidal flat within the Changjiang （Yangtze River） Estuary. Except for NH4^＋, there always showed high fluxes from overlying water into sediment for other four nutrients. Sediments in the high and middle marshes, covered with halophyte and consisting of macrofauna, demonstrated more capabilities of assimilating nutrients from overlying water than the low marsh. Sampling seasons and nutrient concentrations in the overlying water could both exert significant effects on these fluxes. Additionally, according to the model provided by previous study, denitrification rates, that utilizing NO3- transported from overlying water （Dw） in Dongtan sediments, were estimated to be from -16 to 193 μmol·h^-1·m^-2 with an average value of 63 μmol·h^-1·m^-2 （n=18）. These estimated values are still underestimates of the in-situ rates owing to the lack of consideration of DN, i.e., denitrification supported by the local NO3^- production via nitrification.     

Changes in nutrient uptake of phytoplankton under the interaction between sunlight and phosphate in the Changjiang （Yangtze） River Estuary

We conducted ship-board incubation experiments to investigate changes in nutrient uptake of phytoplankton under different phosphate concentrations and irradiances in the Changjiang River Estuary and its adjacent waters in China. Under 100% natural irradiance the uptake rates of phosphate, silicate, and nitrate were accelerated at high phosphate levels （1.84 μM）, while under low irradiance （about 50% natural irradiance） their uptake rates were restrained at the high but stimulated greatly at the intermediate phosphate concentrations （1.26 μM）, as the growth of phytoplankton, changes in nitrite and ammonium uptake didn＇t follow an obvious pattern. Our results also showed that there were linear relationships between nitrate, silicate and phosphate uptake at different phosphate concentrations under low and high irradiances, and the growth period of phytoplankton was prolonged both at the high phosphate concentrations under high irradiance and at the intermediate concentrations under low irradiance, suggesting that the limitation of phytoplankton growth mainly reflected changes in its growth period, and because no such environment （low irradiance and low phosphate concentrations） actually existed in a high turbidity zone, phytoplankton blooms hardly occurred there. In the absence of irradiance, denitrification occurred readily and phytoplankton was kept decreasing, which resulted in phosphate regeneration.     

<Superscript>40</Superscript>Ar-<Superscript>39</Superscript>Ar dating of lamprophyre dykes in the Baimazhai nickel deposit,Yunnan Province,China, and its geological significance

The Baimazhai nickel deposit, Yunnan Province, China, is located in the southern part of the Sanjiang （Tri-river） alkali-rich intrusive rock belt （Sanjiang ARIR）. In this paper was conducted ^40Ar-^39Ar dating of two phlogopites in lamprophyres which are, as dikes, widely distributed in the orefield, and two plateau ages were acquired, i.e., 32.46±0.62 Ma and 32.01±0.60 Ma, respectively （averaging 32.23±0.60 Ma）. The ages are obviously younger than those of the ore-hosted complex and mineralization of the Baimazhai nickel deposit. In combination with the characteristics, it is indicated that lamprophyres in the orefield and those in the Sanjiang ARIR are similar in tectonic setting, mineral assemblage and geochemistry. It is considered that lamprophyres in the orefield are the important component of the Sanjiang ARIR, and the lamprophyres and ore-hosted complex in the orefield represent the products of two times of different magmatic activity from different mantle sources. On the other hand, the age of lamprophyres in the orefield is older than that of the strike-slip shearing of the Ailaoshan-Honghe fault belt, suggesting that the strike-slip shearing of the Ailaoshan-Honghe fault belt is not the factor leading to magmatic activity of lamprophyres in the orefield, while it is more possible that magmatic activity of the Sanjiang ARIR promoted strike-slip shearing of the fault belt.     

地震瞬时属性分析技术在岩溶勘查中的应用

介绍地震瞬时属性分析技术的原理及处理方法,分别对岩溶在地震剖面、瞬时振幅剖面、瞬时频率剖面、瞬时相位剖面上的表现特征作了说明.并结合实际资料进行多参数解释,进而确定地下岩溶的发育情况、分布范围和规模,同时对异常进行钻井验证,结果表明,地震瞬时属性分析技术比常规地震处理方法能更好地排除干扰,确定岩溶异常.     

红旗渠任村镇白家庄至尖庄段一带地质灾害体特征及其稳定性评价

红旗渠是举世文明的引水工程,全长4 013.6 km.红旗渠沿线地质条件极为复杂,地质灾害频繁发生.林州市任村镇白家庄至尖庄一带为本次工作的勘查区,勘查中共发现零星崩塌3处,崩塌带1处、沟谷泥石流3处.本文针对发现的地质灾害的类型、规模、形态等进行描述并给以稳定性评价.     

视电阻率曲线在研究聚煤盆地沉积环境分析及聚煤规律中的应用

分析聚煤盆地沉积环境,研究聚煤盆地煤层分布规律,对指导煤田预测和指导勘探工作有着重要的作用。充分利用数字测井的视电阻率曲线来分析、解释原始沉积环境,研究聚煤盆地的煤层分布特点,具有一定的现实意义。     

地形因素对航空面阵CCD影像的影响分析与评价

地形因素,包括地面起伏和地球曲率,是造成航空数字遥感影像变形的主要原因之一.本文以中国科学院遥感所自行研发的多模态航空CCD相机系统为对象,结合其成像模式和几何形态,分析了地形因素给影像带来的变形,推导出航空面阵CCD影像变形的一般公式,并通过概算进行了定量评价,得出了对于航空面阵CCD影像,要想得到高精度的几何处理,必须改正地球曲率影响的结论.     

北山霍勒扎德盖石炭系扫子山组岩石地层及古孢子化石特征

甘肃山北部霍勒扎德盖地区,分布着一套火山—沉积地层,对其进行岩石地层、区域对比及地层年代等方面的研究,划归扫子山组,并依据组内岩性差异划分为4个岩性段。该组的确定对研究哈萨克斯坦板块南缘地质演化历史有重要意义。     

长白山生态景观格局动态变化分析

长白山独特的地质和地理条件,形成了特有的自然景观,植被垂直带谱在亚洲具有代表性。通过1977年MSS、1985年TM及1999年TM三期遥感影像,结合实地调查建立解译标志,进行分类并计算景观指数,分析了长白山地区近30年来的景观结构变化。分析表明：从景观面积变化率来看,1977-1985年间,水体、苔原、居民点、针叶林和草地的面积减少,耕地和针阔混交林的面积增加显著,阔叶林、岳桦林、道路、裸地增加;1985-1999年间,水体、裸地、针阔混交林和阔叶林的面积减少,其他类型面积增加。景观格局变化表明,人为活动对景观格局产生的影响,已成为景观格局变化的主要驱动因子。